LASER means Light Amplification by Stimulated Emission of Radiation , It can produce an intense , highly directional beam of light , The most popular cause of laser-induced tissue damage is the thermal in nature , The tissue proteins are denatured due to the temperature rise following absorption of the laser energy .

Laser radiation

Human body is vulnerable to the output of certainlasers, The exposure tolaser radiation can result in damage to the eye & the skin , The human eye is almost always more vulnerable to the injury than the human skin .

Laser hazards are addressed in specific standards for the general industry , The workers have a right to a safe workplace , The law requires the employers to provide their employees with safe and healthful workplaces .

Laser safety standard & Safety Precautions

Main purpose of laser safety standard is to preventthe laserrelated injuries , The safety protection againstthe laserscan be attained when the users correctly recognize the potential hazard of laser products and they correctly perform a specific procedure using safety functions of laser products .

Laser goggles

You should take safety measures for class 4laserproducts , To prevent operation of the laser system by unauthorized users , the key control ( Key operated power switch ) should be managed by the Laser Safety Officer.

You have to connect the remote interlock ( emergency stop ) input terminal ( remote interlock connector ) ofthe lasersystem to the emergency stop switches or the like to prevent laser radiation in an emergency .

You have to post a warning sign at the entrance to the controlled area in which the laser product is installed to ensure that the workers and outsiders are informed about the dangers .

If the skin is exposed to the laser beam reflected on the marking target in the control area where the laserproduct is installed , It will cause the skin to burn , and the clothes may catch fire , During the laseroperation , wear the flame-resistant clothes and protect the skin as much as possible .

You have to protect your eyes by protective goggles in the controlled area in which the laser product is installed , You have to wear protective eye goggles , regardless of whether normal use or maintenance , in case of accidental exposure to the laser emission .

You should select protective goggles which are appropriate for the laser light wavelength , Wear protective eye goggles whose optical density for the 10.6 μm wavelength is between 5 and 7 , You should not wear the protective eye goggles with the optical density exceeding 7 , Otherwise the laser radiation emissionindicator may not be visible .

The laser goggles can protect the eyes from the reflected or scattered laser light with the hazardous beam power , as well as from the direct exposure to the laser beam , Even when wearing the protective eye goggles , avoid the eye exposure to direct or scattered laser radiation .

The eye-wear must be selected for the specific type of laser , to block or attenuate in the appropriate wavelength range , The eye-wear absorbing 532 nm typically has an orange appearance (although one should never rely solely on the lens color when selecting laser eye protection ) , transmitting wavelengths larger than 550 nm .

Eye-wear is rated for the optical density (OD) , which is the base-10 logarithm of the attenuation factor by which the optical filter reduces beam power , Eye-wear with OD 3 will reduce the beam power in the specified wavelength range by a factor of 1000 .

The acrylic filter can be attached to the monitoring window on the equipment to block the laser beams , If the poisonous gas is generated duringthe lasermarking on the target object , identify the substances produced by the gas and provide a local ventilation system .

You should appoint the safety officer who has a big knowledge and experience in handling the laser products to enforce safety management , Laser Safety Officer can manage the key for the key-operated power switch , He can check the protective equipment & its use and he can train the operators .

Laser Safety Officer suggests the prevention measures related to the laser emission , He sets up the laser controlled area ( The area in which there is a risk of exposure to the laser emission from the laser products ) .

You should establish a protective enclosure around the laser marker’s head using a material having the appropriate reflectance and heat characteristic to block the reflected light , It prevent the individuals from being exposed to careless reflected light when the laser marker is operating .

You must not put your eyes at the horizontal plane level where the beams are in case of reflected beams that leave the optical table during the optical experiments , As exposing the eye to the laser radiation or diffuse reflection may cause the blindness .

You must not expose the skin to the laser radiation or the diffuse reflection , You have to be careful that you do not insert the hand or the other body part into the marking area during the operation ,The laser may cause damage to the skin such as the burns .

If you install the head , You have to terminatethe laserbeam path to avoid the eye or skin exposure to direct or scattered laser radiation ,the laserbeam emitted by ML-Z9500 Series must be terminated at the end of its useful path by a diffusely reflecting material of appropriate reflectivity and thermal properties or by the absorbers .

You have to install ML-Z9500 series so that the path of the laser beam is not as the same height as that of human eye , You should not disassemble ML-Z9500 Series , Otherwise exposure tothe laser radiation and the electric shock may result .

The ML-Z9500 Series is not under warranty and cannot be repaired if it has been disassembled , You have to be sure to turn off MLZ9500 series before performing the maintenance tasks such as cleaning the lens and you should wear protective eye goggles during maintenance .

You should not use ML-Z9500 Series near the flammable materials , You should not place any flammable objects or gas ( organic solvents ) near the laser emission opening of the ML-Z9500 Series as this may cause a fire.

You should not irradiate the laser beam onto mirrored metal materials , The CO2 laser cannot mark metal materials , Never attempt to mark highly reflective metal materials , All non-optical objects that are close to the optical plane should have a matte finish to prevent specular reflections such as the jewelry & watches .

ZnSe ( zinc selenium ) is used for the lens and the other optical parts , ZnSe is treated as a poison by law , Rely on the company which handles the industrial waste when disposing of the product .

You should turn off all power before connecting the controller power cable , Otherwise , It may cause an electric shock , High-intensity beams can cause the fire or the skin damage ( mainly from class 4 and ultraviolet lasers) and which are not frequently modified should be guided through opaque tubes .

You have to eliminate the dust or the fumes occurring during marking using an appropriate dust/fume collector to prevent these particles from entering the human body , Depending on the marking target material , this may cause damage to human body .

Bad effects of laser on the human body

The denaturation ofproteinis due to the heat effect oflaserbeam , The photo-chemical reactions in the cell tissues or the tissue destruction caused by the impact waves ( the plasma flow and resulting pressure waves ) may occur .

Many direct biological effects oflaserdepend on the wavelength , output and output waveform ( continuous wave or pulse wave ) ofthe laser beam , but it is more likely to cause serious , irreversible damage to the eyes rather than to the skin .

The argon laser , YAG laser or CO2 laser , that all radiate continuous or long pulse waves , cause the following problems due to the heat effect or the photo-chemical reactions :

When the wavelength of laser beams is out of the range of perception ( ultraviolet ( 200 to 400 nm ) and near-infrared ( 1,400 to 106 nm )) , They are absorbed in the tissues of cornea or lenses , causing the cataract with corneal burns or visual degradation .

When the wavelength of laser beam is within the range of perception ( visible ( 400 to 780 nm ) and near-infrared ( 780 to 1,400 nm )) , They are focused on the retina because of the eye’s optical systems ( cornea and lens ) and the density becomes approximately 105 times greater , This causes the following problems :

The laser beams which produce continuous waves are absorbed in the retina ( center or vicinity ) and mainly cause the retinal burns due to the heat effect , The visual lasers with the wavelength of approximately 430 nm , that is absorbed in the visual pigments of retinal photoreceptors , mainly cause retinal problems due to the photo-chemical reactions .

YAG/YVO4 (Q-switch) lasers or CO2 lasers , that have a short pulse and high peak power , cause retinal burns or fundal hemorrhage , often resulting in severe visual degradation .